GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 2.3 465 regions of central Italy:Abruzzo, Lazio, Marche, and Umbria.At the end of the seismic sequence, 2,043 AeDES survey forms were filled (Di Ludovico et al., 2017c). Indeed, in several cases, school buildings structures were re-inspected after a new major seismic event. The seismic sequence involved four significant events: M=6.0August 24, M=5.9 October 26, M=6.5 October 30, and M=5.5 January 18. Tab. 1 shows the number of structures inspected after each event of the seismic sequence as well as that of structures already inspected in the previous events. Tab. 1 shows that 1445 different school buildings (about 95%) were inspected in the aftermath of two main shocks of the sequence, namely August 24, 2016 (i.e. 872 buildings) and October 30, 2016 (i.e. 573 buildings never inspected before). Tab. 1 - Number of school structures inspected after the four seismic events. No. 872 school structures inspected after Aug 24 after Aug 24 872 No. 92 school structures inspected after Oct 26 already inspected after Aug 24 36 after Oct 26 56 No. 1,012 school structures inspected after Oct 30 already inspected after Aug 24 400 already inspected after Oct 26 16 already inspected both after Aug 24 and after Oct 26 23 after Oct 30 573 No. 67 school structures inspected after Jan 18 already inspected after Aug 24 11 already inspected after Oct 26 1 already inspected after Oct 30 15 already inspected both after Aug 24 and after Oct 26 - already inspected both after Aug 24 and after Oct 30 18 already inspected both after Aug 26 and Oct 30 1 already inspected after each previous event 8 inspected after Jan 18 13 The location of the 1,445 geo-referenced school building structures inspected in the aftermath of two main shocks and the estimated MCS (Mercalli-Cancani-Sieberg) instrumental intensity shake maps (Istituto Nazionale di Geofisica e Vulcanologia, INGV, http://shakemap. rm.ingv.it/shake/index.html ) related to the two main shocks of the sequence (i.e. August 24 and October 30, 2016) are depicted in Fig. 1a, 1b and Fig. 1c, 1d, respectively. Fig. 1a to 1c also show the usability rating of buildings: usable buildings (A rating, white triangles); unusable building but usable only after short-term countermeasures or partially usable (B or C rating, green triangles); unusable buildings (E rating, red triangles). Fig. 1b shows that the region close to the fault experienced PGA larger than 0.40 g. The area with VI-VII MCS intensities is approximately 100x100 km 2 . The shakemap of the M=6.5 October 30 earthquake (Fig. 1d), shows an overall larger area affected by the VI-VII intensities when compared to the previous earthquakes (ReLUIS-INGV, 2016). The data collected shows that about 85% of the database was located in Municipalities classified with macroseismic intensity in the MCS scale (IMCS) lower than VII, with a similar trend among the two seismic shocks. Out of 1,445 school building structures, 423 (29%) were inspected both after the August 24 and the October 30 seismic event all over the four regions. Note that buildings with initial